check_caa

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true, so the safety profile is covered. The description adds the domain-appropriate semantics (shows which CAs are authorized) but does not elaborate on caching behavior or output format, which would be useful given the force_refresh and format parameters.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no filler. The first sentence states the action and resource, the second clarifies the result's meaning, and the third positions the tool within the scan_domain audit. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple, read-only DNS lookup tool with a fully documented schema, annotations, and an output schema, the description is complete. It covers the tool's purpose and context without needing to explain return values or parameter details.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema provides 100% coverage of all three parameters with descriptions, so the baseline is 3. The tool description does not add extra parameter semantics beyond mentioning 'domain' in prose, but the schema already handles parameter documentation adequately.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Look up') and identifies the exact resource ('CAA records for a domain'), clearly distinguishing it from sibling check_* tools that target other DNS record types. The added context about Certificate Authorities further clarifies the tool's purpose.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context by noting it is 'Part of the scan_domain audit,' implying when it fits into a broader workflow. It does not explicitly list exclusions or alternatives, but for a DNS record lookup tool, the record type in the name/description makes the intended usage obvious.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.